JP5907709B2 - Energy efficient content caching with custodian-based routing in content-centric networks - Google Patents

Description

  The present disclosure relates generally to content routing in content centric networks. More specifically, this disclosure relates to energy efficient content caching with custodian routing in a content centric network (CCN).

  The surge in Internet and e-commerce continues to spur innovative changes in the network industry. Today, there is a great deal of information exchange online, from watching movies online to daily news distribution, retail, and instant messaging. Internet applications are also increasing for mobile applications. However, the current Internet generally operates with a location-based addressing scheme. That is, data consumers can only receive data by explicitly requesting data from an address (eg, an IP address) that is closely associated with a physical object or location. This restrictive addressing scheme is gradually becoming insufficient to meet ever-changing network requirements.

  The current Internet architecture revolves around conversational models created in the 1970s for the ARPANET to allow geographically dispersed users to use a small number of fixed large computers. Yes. This architecture was designed under the influence of the telephone network, which is a program whose telephone numbers basically constitute a switch along the path from the source to the destination. Not surprisingly, ARPANET designers never expected that ARPANET would evolve into today's ubiquitous, ever-growing Internet. People now expect more from the Internet than the purpose offered by ARPANET. Ideally, Internet users should be able to access any content anywhere, anytime, but such access is facilitated by the current location / device binding TCP / IP (Transmission Control Protocol / Internet Protocol) network. It is difficult to do.

  Content centric networks (CCN), also referred to as “content-based networks”, provide a new approach to data transmission in networks. Rather than seeing network traffic at the application level as an end-to-end conversation in which content is communicated, content is requested or returned based on the name given to it, and the network is from provider to consumer Involved in routing data or “content”.

  One embodiment of the present invention provides a system that facilitates custodian-based routing. In operation, the system maps content to a computing device based on the name of the content without using the physical address of the computing device in a computing device that acts as a backup custodian for one or more portable devices. A request for a part of the content is received from the requesting device. The system determines whether the content is available on the computing device. In response to the content not being available on the computing device, the system identifies the mobile device that stores the content and obtains the content from the identified mobile device. The system then stores the content in the cache at the computing device, thereby enabling the computing device to provide the content in response to a subsequent request without connecting to the identified portable device, Provide content to the original device.

  In one variation of this embodiment, the computing device, requesting device, and portable device are connected to a content centric network (CCN).

  In one variation of this embodiment, identifying a mobile device that stores content includes performing a search based on the name of the content, where the name of the content consists of a number of variable length elements.

  In one variation of this embodiment, content stored on the mobile device is mapped to a backup custodian regardless of whether the backup custodian stores content.

  In one variation of this embodiment, connections to the identified mobile device are prohibited from devices other than the backup custodian.

  In one variation of this embodiment, the computing device receives a request for content based on a priority level of the computing device that is higher than the priority level of the mobile device that stores the content.

  In one variation of this embodiment, obtaining content from the identified mobile device identifies a communication endpoint located at the mobile device and establishes a connection to the identified communication endpoint. Including.

  In a further variation, the communication endpoint includes one of a WiFi interface, a cellular phone interface, and a Bluetooth interface.

  In a further variation, establishing a connection to the identified communication endpoint includes using a session initiation protocol (SIP).

FIG. 1 shows a schematic diagram of an exemplary architecture of a CCN-based content distribution network (CDN) having a mobile device and its backup custodian according to an embodiment of the present invention. FIG. 2 shows a schematic diagram of an exemplary backup custodian device architecture according to an embodiment of the present invention. FIG. 3 shows a spatio-temporal schematic diagram of a process of a remote device for acquiring content stored in a mobile device according to an embodiment of the present invention. FIG. 4 illustrates an exemplary computer system that facilitates energy efficient content caching with custodian-based routing across CCNs according to embodiments of the present invention.

  The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments should be readily apparent to those skilled in the art, and the general principles defined herein may be used in other embodiments without departing from the spirit and scope of the invention. And may be applied to applications. Thus, the present invention is not limited to the embodiments shown, but is to be accorded with the widest scope consistent with the principles and features disclosed herein.

  The data structures and codes disclosed in this detailed description are typically stored on a computer readable storage medium, which can be any device or medium capable of storing code and / or data for use by a computer system. Has been. Computer readable media include, but are not limited to, volatile memory, non-volatile memory, disk drives, magnetic tape, CD (compact disc), DVD (digital versatile disc or digital video disc), etc. Includes magnetic and optical storage devices, or other media that can store computer-readable storage media now known or later developed.

  Embodiments of the present invention provide a solution for energy efficient content caching with custodian-based routing in CCN. In a CCN environment that implements custodian-based routing, content is associated with a custodian and a request for content is sent to the custodian of the content. To reduce the energy consumption of mobile devices, frequent content requests for mobile devices are handled by assigned backup custodians, which can be fixed devices that have little or no power limit. Can. All content stored on the mobile device must be mapped to the backup custodian during content prefix-to-custodian mapping, even if the backup custodian does not contain all content Can do. When the remote device requests a piece of content stored on the portable device, the request is directed to the backup custodian based on the content prefix-to-custodian mapping. If the backup custodian does not have a copy of the requested content, it requests a copy from the portable device and stores the copy in the cache to fulfill future requests from other remote devices.

  Although the present disclosure is illustrated using an example based on CCN, embodiments of the present invention are not limited to CCN.

  The term “custodian” refers to a device that stores content corresponding to an interest. A custodian can be any type of device capable of storing data in volatile or non-volatile storage. The custodian can be a laptop computer, a tablet or slate computer, a smart phone, a portable computing device such as a personal digital assistant (PDA), or a fixed computing device such as a desktop computer or home media server. .

  The term “communication endpoint” refers to a communication interface in a computing device through which a remote device can communicate with a computing device. “Communication endpoints” include, but are not limited to, WiFi ™ (a trademark of Wi-Fi Alliance) interface, third generation mobile phone interface, and Bluetooth ™ (Bluetooth in Kirkland, Washington). Any type of communication interface, including a Special Interest Group trademark) interface.

  The CCN name can include a clearly specified number of elements. Furthermore, CCN names are persistent and content specific. That is, when the user changes the content of a file or data object, the changed content is effectively associated with a new name. This persistence can be achieved, for example, by a well-defined versioning mechanism in which new content can be “version 4” of the predetermined name. The version is usually a timestamp. Persistence can also be realized implicitly. For example, content can be associated with authentication metadata (eg, a digital signature by the publisher of the content) as well as the name that they have defined. As a result, the complete content name changes when the data associated with the predetermined name changes.

  In a content-centric network (CCN), communications are driven by data consumers. There are two packet types in the CCN: interest and data. An interest packet (also referred to as a “query”) is a request for some content. The interest packet encodes a special form of query that indicates the desired content. A data packet (also referred to as a “content packet”) is a unit of content. Data packets are self-identifying by having their full name inside. A consumer can ask for content by broadcasting its interest across all available connectivity. Any node that has data that listens to and satisfies that interest can respond with one or more data packets. Data is sent only in response to an interest and consumes that interest. Both interest and data identify the content to be exchanged by content name (or CCN name). In one embodiment, data may “fill” interest if the CCN name in the interest packet is a prefix of the CCN name in the data packet. The interest may specify the exact version to search, or may specify any version that is larger than the specified version known as “latest version acquisition interest”.

  Functionally, CCNs can hold associations between various names and the content they represent. Names are built hierarchically, have a variable length, and can be understood by the user in many situations. For example, “/ abcd / bob / papers / ccn / news” is the name of the article, ie “news” from the “ccn” collection of documents for a user named “Bob” in an organization named “ABCD”. Can be an article. In CCN, from an application perspective, content consumers do not need to determine how to find the “ABCD” organization or which host holds Bob's CCN publication. In one embodiment, in order to request a piece of content, a device at the CCN registers with the network interested in the content by its name and, if available in the local network, the content Will be returned. The routing infrastructure intelligently propagates the interest to the expected issuer and takes care to return any available content along the path that the interest has taken.

  CCNs have additional properties that make them particularly attractive. All content can be cryptographically authenticated, which means that some small group of nodes on the network (for example, the right questioner of the content) can verify the authenticity of some of the content Means. The CCN also allows data to be accessed by name, independent of the issuer. At the same time, special requests for data can be coordinated by an issuer. For example, “foo.txt” or “foo.txt” signed by Bob can be determined. Any form of self-verifying name can be used as a contract between the producer and the consumer. It is also possible to use a hybrid self-verification name. Here, the first half component of the name is for organization and efficient routing, and the second half component of the name is self-verification. Finally, CCN allows separation of content and trust, allowing different data consumers to use different mechanisms to establish trust in the same piece of content. The content may be signed by a single publisher, which can be trusted for different reasons. For example, one user may trust a certain piece of content for a direct personal connection with the signer, while the other user appears to trust that user. The same content may be trusted for participation of the content signer in the public key infrastructure (PKI) selected for.

  Custodian-based routing is implemented across a CCN-based content delivery network (CDN) that includes different user devices to enable sharing of content between different user devices within a social network group Can do. In a CDN that implements custodian-based routing, content is associated with a device that stores content called custodian. Requests for a particular piece of content can always be sent to a custodian regardless of the custodian's physical location.

  In order to ensure that some requesters of content can accurately connect to the custodian of that content, the CCN-based CDN provides content prefix-to-custodian mapping, custodian-to-two It maintains three different mappings, including communication endpoint mapping and communication endpoint-to-physical address mapping. Each time a device interacts with another device, the device exchanges three types of mapping information with each other to ensure that routing information is assigned across the CCN. Instead, the communication endpoint-to-physical address mapping information is stored in a third party service such as a public session initiation protocol (SIP) server that provides a rendezvous service between the requester and the custodian. Can do.

  Details on custodian-based routing can be found in the inventor James D. Thornton, Van L. It can be found in US Patent Application No. TBD (Attorney Docket Number PARC-20100168-US-NP) entitled "Custdian-based Routing in Content Centric Networks" by Jacobson and Mark Mosco, The disclosure is incorporated herein by reference in its entirety.

  In custodian-based routing, a content custodian is responsible for providing content to other requesting devices. However, for energy limited portable devices such as battery powered cell phones, responding to frequent requests for stored content can lead to a rapid waste of battery power. For example, a user takes a video using a mobile phone and notifies the whole family who wants to share the video. Thus, the entire user's family will attempt to connect to the user's phone and download the video file. Multiple download attempts can cause a user's mobile phone to quickly drain because a significant amount of power can be consumed each time a file is downloaded.

  To address such issues, embodiments of the present invention allow a mobile device to delegate content distribution tasks to a non-power limited fixed device as its backup custodian. The content stored on the mobile device can be stored in the content prefix-to-custodian mapping table with different performance settings regardless of whether such content is physically stored on the backup custodian. Maps to both backup custodians.

  FIG. 1 shows a schematic diagram of an exemplary architecture of a CCN-based CDN having a portable device and its backup custodian according to an embodiment of the present invention. The CDN 100 includes a number of devices such as a laptop computer 102, a media server 104, and smartphones 106-110 connected to each other via a CCN 112.

  In order to avoid battery waste due to frequent content requests, the smartphone 106 can interact with the backup custodian as a backup custodian by mapping the stored content to the media server 104 in addition to the smartphone 106. AC) Specifies the media server 104 connected to the power source. As a result, each piece of content stored on the smartphone 106 has at least two custodians, the smartphone 106, and the media server 104. In order to facilitate this configuration, the smartphone 106 first notifies the media server 104 of a namespace prefix that the media server 104 needs to provide a backup service. For example, the smartphone 106 may want the media server 104 to be a backup for all its videos, but not photos. Therefore, the smartphone 106 transmits the namespace prefix “/ Bob cell / video” to the media server 104. Such notification can be sent to the media server 104 via CCN or other communication channel. Furthermore, the smartphone 106 notifies the media server 104 of the priority of the prefix-to-custodian entry (PCE) that maps the namespace prefix to the smartphone 106. Upon receiving the namespace prefix, the media server 104 generates a PCE that maps the namespace prefix to the media server 104. To ensure that the media server 104 is contacted in front of the smartphone 106, the PCE mapped to the media server 104 has a higher priority than the PCE mapped to the smartphone 106. Composed. It should be noted here that a device with a higher priority has a higher connection priority. As a result, any request for content under these namespaces is initially directed to the media server 104 that is not power limited and therefore capable of handling frequent content requests. Instead, to ensure that content requests are directed to the media server 104, the smartphone 106 specifies that the media server 104 is the only device allowed to connect to the smartphone 106. Can do. To that end, in one embodiment, the entry in the custodian-to-endpoint mapping table corresponding to the smartphone 106 includes a restriction entry that indicates which devices are allowed to connect. These restrictions are included in the endpoint attribute entry (EAE) for all endpoints associated with the smartphone 106. In one embodiment, the restriction entry indicates that devices other than the media server 104 are not allowed to connect to the smartphone 106.

  When the smartphone 108 attempts to obtain a portion of the content stored on the smartphone 106, it performs a search on the content prefix-to-custodian mapping information. The search result indicates that the backup custodian for the smartphone 106, that is, the custodian for the requested content is the media server 104. Note that the smartphone 108 does not need to know the physical address of the media server 104 when performing a search. Thus, the smartphone 108 establishes a connection to the media server 104 instead of to the smartphone 106 to request content. When the media server 104 receives a content request, it determines whether it has a copy of such content. If so, the media server 104 provides the requested content to the smartphone 108. If not, the media server 104 determines which device is actually storing the requested content. If the media server 104 knows itself as a backup custodian of the smartphone 106, the media server 104 can assume that no content is stored on the smartphone 106. Instead, the media server 104 can perform a search on its content prefix-to-custodian mapping information to locate the actual content custodian.

  Once the smartphone 106 is identified as an actual device that stores the requested content, the media server 104 connects to the smartphone 106 to obtain the requested content. Because custodian-based routing maintains a custodian endpoint-to-physical address mapping as well as a custodian-to-communication endpoint mapping, the media server 104 is independent of the physical location of the smartphone 106. It is possible to establish a connection with the smartphone 106. Note that if the media server 104 and the smartphone 106 are both connected to the same WiFi network, the media server 104 can connect directly to the smartphone 106 via the WiFi network. That is. Otherwise, other types of communication channels such as peer-to-peer tunnels negotiated by Session Initiation Protocol (SIP) may be required to connect the media server 104 with the smartphone 106. Upon receiving content from the smartphone 106, the media server 104 stores a copy of the content in its local cache and passes the content to the smartphone 108. Later, when another remote device such as the smartphone 110 requests the same content, the media server 104 provides the cached content to the other remote device instead of having to connect to the smartphone 106 again. can do. In this way, multiple remote devices can obtain content stored on the smartphone 106 without multiple connections to the smartphone 106, thus avoiding smartphone 106 battery waste.

  FIG. 2 shows a schematic diagram of an exemplary backup custodian device architecture according to an embodiment of the present invention. The backup custodian device 200 includes a receiving mechanism 202, a CCN daemon module 204, a routing agent 206, a routing table 208, a local cache 210, and a transmission mechanism 212.

  In operation, the receiving mechanism 202 receives a request for certain content from a remote device. It should be noted that the remote device has identified the backup custodian device 200 as the custodian of the content. The receiving mechanism 202 passes the received request to the CCN daemon module 204 that is configured to execute a background process for the CCN. The CCN daemon module 204 checks the local cache 210 to determine if the content is locally available. If so, the transmission mechanism 212 transmits the requested content to the requesting remote device. If not available, the CCN daemon module 204 contacts the routing agent 206 to obtain routing information to determine the actual custodian that stores the requested content. In one embodiment, the routing agent 206 obtains routing information from the routing table 208 including content prefix-to-custodian mapping. In a further embodiment, the routing table 208 stored in the backup custodian device 200 is different from the routing table assigned between other CCN devices. In the routing table assigned between CCN devices, the backup custodian device 200 is a portable device that is backed up by the backup custodian device 200 regardless of whether its contents are physically located in the backup custodian device 200 or not. Specified as the custodian for all the content stored in. In contrast, the routing table 208 stored in the backup custodian device 200 maps the mobile device as the actual custodian of the content.

  Once the actual custodian of the content is identified, the backup custodian device 200 can establish a connection with the actual custodian and obtain the requested content. The backup custodian device 200 creates a copy of the requested content and stores this copy in the local cache 210. Thereafter, the transmission mechanism 212 transmits the requested content to the remote device.

  FIG. 3 is a space-time schematic diagram illustrating a process of a remote device for acquiring content stored in a mobile device according to an embodiment of the present invention. In operation, the requesting device 302 receives a request from the user for a piece of content that is not locally available (step 308). Upon receiving the request, the requesting device 302 performs a content prefix-to-custodian search to determine the content custodian (step 310). In one embodiment, the search results indicate that the custodian with the highest priority for the requested content is the media server 304 that is the backup custodian for the mobile device 306. In a further embodiment, the search results indicate that the media server 304 is the only content custodian that allows the requesting device 302 to establish a connection. Based on the search results, the requesting device 302 connects to the media server 304 to request content (step 312).

  Upon receiving the content request, media server 304 determines whether it actually has a copy of such content (step 314). If so, the media server 304 provides the requested content to the requesting device 302 (step 316). If not, the media server 304 identifies the actual custodian of the requested content (step 318). In one embodiment, the media server 304 performs a content prefix-to-custodian search to identify the actual custodian. It should be noted that the media server 304 functions as a backup custodian for a plurality of portable devices. By performing a content prefix-to-custodian search, the media server 304 can find out which mobile device actually stores the requested content. In one embodiment, the media server 304 maintains a content prefix-to-custodian mapping table that maps content prefixes to the actual custodians of the content.

  Once the media server 304 identifies that the mobile device 306 stores the requested content, it establishes a connection with the mobile device 306 to request the content (step 320). In one embodiment, the media server 304 establishes a connection to the mobile device 306 by performing a custodian-to-communication endpoint search and a communication endpoint-to-physical address search. The custodian-to-communication endpoint mapping information provides a mapping between a custodian and an endpoint that allows a possible path for a given custodian. In one embodiment, the custodian-to-communication endpoint mapping information is included in a custodian-to-communication endpoint mapping table that is exchanged between devices in the CCN. In the custodian-to-communication endpoint mapping table, each device in the CCN has a corresponding entry that includes an array of custodian endpoint entries (CEEs) corresponding to all endpoints belonging to the device. For example, the entry corresponding to the mobile device 306 may include a WiFi interface, a third generation mobile phone interface, and a Bluetooth interface. The CEE corresponding to the endpoint is also an endpoint attribute entry (EAE) component that can be used to identify which devices are allowed to obtain a piece of content from the endpoint. Can be included. The mobile device 306 can use the EAE component to identify that the media server 304 is the only device allowed to connect to any of its endpoints.

  Communication endpoint-to-physical address mapping provides the information needed for rendezvous between devices. Such mapping information can be stored in a custodian-to-communication endpoint mapping table or stored in a third party service such as a public SIP server that provides a rendezvous service. it can. For example, the mobile device 306 can register its SIP address with a public SIP server.

  After establishing the connection, the portable device 306 provides the requested content to the media server 304 (step 322). Upon receiving the content, the media server 304 stores a copy of the content in the cache (step 324) and provides the content to the requesting device 302 (step 326).

  By storing the content originally stored in the mobile device 306 in the cache at the media server 304, the media server 304 can supply subsequent requests for the same content from other remote devices. As a result, the mobile device 306 only needs to deliver the desired content once, and therefore provides an energy efficient way of content sharing.

  FIG. 4 illustrates an exemplary computer system that facilitates energy efficient content caching with custodian-based routing across CCNs according to embodiments of the present invention. In FIG. 4, the computer and communication system 400 includes a processor 402, a memory 404, and a storage device 406. The storage device 406 stores a program to be executed by the processor 402. Specifically, the storage device 406 stores the content caching application 408 along with other applications such as the applications 410 and 412. In operation, content caching application 408 is loaded from storage device 406 into memory 404 and then executed by processor 402. While executing the program, the processor 402 performs the functions described above. Computer and communication system 400 is connected to an optional display 414, keyboard 416, and pointing device 418.

Claims (10)

One or more mobile devices function performs computing device as a backup custodian for receives a request for some content from the requesting device,
The request identifies the content by name without using the physical address of the computing device,
Content it is determined whether or not available on the computing device,
In response to the content not being available on the computing device,
Perform a content prefix-to-custodian mapping search to identify the mobile device that stores the content ,
Performing a custodian-to-communication endpoint search and a communication endpoint-to-network address search to determine a network address of the content;
Generate a request to retrieve content from the identified mobile device,
Sending the request to the identified mobile device to obtain content from the identified mobile device;
In response to receiving the content from the identified mobile device,
Store the content in the cache on the computing device,
It provides content in response to requests after without connection to the identified mobile device,
Providing content to the requesting device;
Computer-executable method.   The method of claim 1, wherein the computing device, the requesting device, and the mobile device are connected to a content centric network (CCN).   The method of claim 1, wherein identifying a mobile device that stores content includes performing a search based on a name of the content consisting of a number of variable length elements.   The method of claim 1, further comprising mapping content stored on the mobile device to the backup custodian regardless of whether the backup custodian stores content.   The method of claim 1, further comprising prohibiting a device other than the backup custodian from connecting to the mobile device storing the content.   The method of claim 1, wherein the computing device receives a request for content based on a priority level of the computing device that is higher than a priority level of a mobile device storing the content.   The content of claim 1, wherein acquiring content from an identified mobile device comprises identifying a communication endpoint located at the mobile device and establishing a connection to the identified communication endpoint. Method. The communication endpoint is
WiFi interface,
A mobile phone interface;
The method of claim 7, comprising one of a Bluetooth interface.    The method of claim 7, wherein establishing a connection to the identified communication endpoint includes using a Session Initiation Protocol (SIP). In a persistent computer readable storage medium that stores instructions that, when executed by a computer, cause the computer to perform the method, the method comprises:
One or more mobile devices function performs computing device as a backup custodian for receives a request for some content from the requesting device,
The request identifies the content by name without using the physical address of the computing device,
Content it is determined whether or not available on the computing device,
In response to the content not being available on the computing device,
Perform a content prefix-to-custodian mapping search to identify the mobile device that stores the content ,
Performing a custodian-to-communication endpoint search and a communication endpoint-to-network address search to determine a network address of the content;
Generate a request to retrieve content from the identified mobile device,
Sending the request to the identified mobile device to obtain content from the identified mobile device;
In response to receiving the content from the identified mobile device,
Store the content in the cache on the computing device,
It provides content in response to requests after without connection to the identified mobile device,
Providing content to the requesting device;
A persistent computer-readable storage medium.

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